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171.
Russian Journal of Coordination Chemistry - Two Mo(VI) clusters, (H2L)3[Mo7O12(μ2-O)8(μ3-O)4] · 3H2O (I) and (H2L)2[Mo8O14(μ2-O)6(μ3-O)4(μ5-O)2] · 4DMF (II),... 相似文献
172.
We prove the well-posedness of a general evolution reaction–nonlocal diffusion problem under two sets of assumptions. In the first set, the main hypothesis is the Lipschitz continuity of the range kernel and the bounded variation of the spatial kernel and the initial datum. In the second set of assumptions, we relax the Lipschitz continuity of the range kernel to Hölder continuity, and assume monotonic behavior. In this case, the spatial kernel and the initial data can be just integrable functions. The main applications of this model are related to the fields of Image Processing and Population Dynamics. 相似文献
173.
We perform first-principles calculation to investigate electronic and magnetic properties of Co-doped WSe2 monolayer with strains from −10% to 10%. We find that Co can induce magnetic moment about 0.894 μB, the Co-doped WSe2 monolayer is a magnetic semiconductor material without strain. The doped system shows half-metallic properties under tensile strain, and the largest half-metal gap is 0.147 eV at 8% strain. The magnetic moment (0.894 μB) increases slightly from 0% to 6%, and jumps into about 3 μB at 8% and 10%, which presents high-spin state configurations. When we applied compressive strain, the doped system shows a half-metallic feature at −2% strain, and the magnetic moment jumps into 1.623 μB at −4% strain, almost two times as the original moment 0.894 μB at 0% strain. The magnetic moment vanishes at −7% strain. The Co-doped WSe2 can endure strain from −6% to 10%. Strain changes the redistribution of charges and magnetic moment. Our calculation results show that the Co-doped WSe2 monolayer can transform from magnetic semiconductor to half-metallic material under strain. 相似文献
174.
《Tetrahedron: Asymmetry》2014,25(24):1630-1633
Heterogeneous catalytic hydrogenation of acetoacetic acid esters over tartaric acid/NaBr-modified Ni powder was determined to be a critical function of the steric bulk of the ester moiety to afford quantitatively 3-hydroxybutyrate in 94% enantiomeric excess when ethyl and i-butyl esters are used, providing a facile route to optically active 3-hydroxybutyrates. 相似文献
175.
The dinuclear zinc complexes as high performance catalysts were used to catalyze phospha-Michael reaction of exocyclic α,β-unsaturated benzocyclic ketones under mild conditions, and the desired products possessing 1-indanones or 1-tetralones skeleton were obtained with excellent enantioselectivities of up to 99%/99% ee and yields of up to 99%. The absolute stereochemistry of the major products catalyzed by (R,R)-L1 was determined to be the (R,R)-configuration by X-ray crystallographic analysis of 3d. A positive nonlinear effect was observed and the possible mechanism was proposed. 相似文献
176.
A discrete predator-prey system with square root functional response is presented. We study the existence and local stability analysis of the system. The conditions of existence of flip and Niemark-Sacker bifurcations in the system are derived. Furthermore, the chaotic behavior of the system in the sense of Marotto is proved. Numerical simulations are performed to show the consistence with analytical results and also to exhibit the complexity of the system. Finally, chaos control in the system is achieved via OGY feedback control method. 相似文献
177.
A sensitively electrochemical aptasensor was developed to detect zearalenone, utilizing DNA assembly based on hybridization chain reaction to amplify the signal current and exonuclease III to reduce the background current. The linear range 5.0×10−5 ng/mL-50 ng/mL, and the limit of detection is 0.013 pg/mL. The fabricated aptasensor showed the high specificity toward aflatoxin B1 (AFB1), fumonisin B1 (FB1) and ochratoxin A (OTA), good repeatability and reproducibility. In addition, the average recoveries of spiked corn and beer samples were in the range of 89 % to 102 %. The established method is of great significance in the field of food safety detection. 相似文献
178.
The cyclopalladated ferrocenylimine adducts Ia , Ib , Ic were evaluated in the Suzuki cross‐coupling reaction of benzyl halides with arylboronic acids. The tricyclohexylphosphine adduct Ia exhibited highly catalytic activity for the coupling of aryl and heteroaryl boronic acids containing various functional groups with benzylic bromides and chlorides (up to 99% yield), furnishing diarylmethane derivatives with low catalyst loading (1 mol%). It is worth noting that catalyst Ia can be reused eight times without losing its catalytic activity. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
179.
Cheng-Gang Li Jin-Cheng Zhou Yan-Fei Hu Bao-Zeng Ren Jun-Tao Bai Xian-Ke Hu Wen Yang 《Journal of Cluster Science》2018,29(3):459-468
Besides the size and structure, compositions also dramatically affect the properties of clusters. In fact, the increased degree of freedom poses much more challenges to determine the global minimum structure of multi-component clusters. In this thesis, based on the CALYPSO structure searching method, the global minimum structures are obtained for ScnNm (n + m=10) clusters at PW91/6-311+G(d) level. The growth behavior indicates that the cage unit tends to arrange into the compact configurations, and the occupied positions of N atoms shift from the surface towards the center of coordination site with the increasing number of Sc atoms. The relative stabilities have been discussed by analyzing the average binding energies and HOMO–LUMO gaps. In addition, the molecular orbitals, dipole moments, polarizability, hyperpolarizabilities, natural population, natural electron configuration, and Infared and Raman spectra calculations allow complete characterization of the electronic and vibrational properties for the global minimum structural clusters. 相似文献
180.